The real issue is this concept of putting a frame in a website that you click on and then automatically does something with your credentials on another site. It

The real issue is this concept of putting a frame in a website that you click on and then automatically does something with your credentials on another site. It really should be handled by a browser toolbar plugin (for those who want this obnoxious feature) not by something that sites can embed to use your credentials as they see fit. It's fundamentally insecure.